re: Tile Advice - All the questions I asked when i joined - Answered
Background Preperations,
Gypsum Plasterboards
Make sure the boards are dry and free from dust, they must be securley fixed and must be rigid, make sure the fixings are flush to the surface, plasterboard usually has two different surfaces, the surface that is intended to take the finish should be exposed. Before tiling, prime with a suitable primer, NOT PVA, something like Bal Prime APD. Allow the primer to dry before tiling.
Newly Plastered Walls
Dont make the mistake of rushing to tile on new plaster, it must be allowed to dry fully before tiling. 4 Weeks should suffice, try and leave a window open to allow air to circulate over the plaster. Make sure the surface is free from dust and loose plaster.
If the plaster has been finished to a shiny, smooth glass like surface brush over it with a stiff brush. Before tiling, prime with a suitable primer as per the manufactures instructions before you tile. If any plaster is loose it will need to be removed and any gaps refilled with fresh plaster or a suitable filler.
Tiling over existing tiles
You need to bare in mind, weight ratings for the surface underneath the existing tiles, the size of the old and new tiles and the weight. If possible remove the old tiles.
If you cannot remove the old tiles, and are sure that the weight of the old and new tiles will be within safe limits then ensure the existing tiles are securley fixed and not at all loose. Score the surface of the existing tiles, and wash down with a suitable sugar soap. wash again to remove and sugar soap residue then tile.
Plywood
Make sure that if overlaying, the existing floorboards are secure and dry, lay the ply sheets with the cross joints staggered leaving a 1/2 to 1mm gap between boards, screw down at 300mm centres, make sure the screws are flush to the surface. Prime (not pva) then tile.
Concrete / Screed base
Ensure new bases have been allowed to dry completley, 6 weeks for concrete, 3 weeks for sand:cement screeds.
Tile Backer board
Fix securley, make sure they are dry and rigid, No need to prime prior to tiling
Tiling over screeded floors with UFH
Allow cement screeds to dry out for three weeks, unless quicksetting cement used. Once dryed out fully, turn on the UHF an allow it to heat 5 d/c per date, until a temp of 25 d/c is reached, leave the UHF on at 25 d/c for three days then allow it to cool to normal room temp. Once tiled leave the UHF off for two weeks, then raise the UHF to desired temp at no more than 5 d/c per day.
